Aspirating piston and plunger coupling



Dec- 24, 1963 s. J. sARNox-F ASPIRATING PIsToN AND PLUNGER couPLINGFiled March 12, 1962 Mmmm INVENTOR.

J. Sarnoff ATTORNEY United States Patent Olice 3,ll5,l35 Patented Bec.24, 1%63 3,115,35 ASIIRATENG PISTN AND PLUNGER CUPLING Stanley l'.Sarnoif, 3 Paolis Hill Road, Bethesda 14, Md. Filed Mar. 12, 1962, Ser.No. 179,085 9 Claims. (Cl. 12S- 213) This invention relates to ahypoderrnic cartridge holder and associated cartridge.

In a common form of hypodermic injection apparatus, there is provided aone-use cartridge of medicament. This cartridge usually includes ahollow needle at one end thereof and a piston at the other end, withfluid medicament therebetween. When the cartridge is inserted within acartridge holder, a plunger forming part of the holder may be coupledwith the piston and then forced in to move the piston toward the needleto expel the fluid content of the cartridge through the needle.

It is an object of this invention, in such a device, to provide forautomatic coupling and decoupling of the piston and plunger.

It is a further object of the invention to provide in such an automaticcoupling and decoupling device a structure to enable withdrawal oraspirating movement of the piston, after the needle has been insertedinto the body of a patient, to ascertain whether the needle has beeninserted into a vein or artery.

Other objects will be made clear upon consideration of the followingspecification when taken in conjunction with the accompanying drawingsin which:

FIG. 1 is a plan View, partly in section, of one form of holderembodying a plunger and coupling arrangement of the invention;

FIG. 2 is a plan view of a cartridge embodying a piston coupling formingpart of the invention;

FIG. 3 is a plan View and partly in section, of a modifled form ofholder and cartridge embodying the invention, showing the cartridgepartially inserted in the holder and in coupled relationship to theplunger;

FIG. 4 is a view of the parts of FIG. 3, with the cartridge in operativeposition and the plunger coupled to the piston;

FIG. 5 is a plan View of the plunger, partly in section;

FIG. 6 is an end view of the coupling end of the plunger;

FIG. 7 is a plan view of a button forming part of the coupling means;

FIG. 8 is a plan View, partly in section, of the coupling end of adifferent form of plunger.

Referring to the drawings with greater particularity, in FIGS. l and 2there are illustrated a holder 10 and a cartridge 12.

The holder comprises a barrel 14 which may be windowed as at 16 toexpose a cartridge therewithin and provided at one end with aninternally threaded opening 1S to threadedly receive the threads Ztl onthe needle end of the cartridge 12. The opposite end of the barrel isopen and its outer wall is provided with two diametrically opposed pins22 pivoting a hub 24 by means of two legs 26 integral with the hub,straddling the barrel and pivoted on the pins. The hub may further beprovided with finger pieces 28 for convenience in manipulation of theholder. Reciprocable in -a bore 29 centrally located in the hub is aplunger 3i), the bore in the hub being of a size to snugly slidablyaccommodate the plunger, especially the right-hand end thereof, as seenin FIG. 1.

The cartridge 12 comprises a glass or plastic tube 32 containing a fluidmedicament 33 and mounting a hollow needle 34 at one end with itspassageway in communication with the medicament in the tube. The otherend of the tube has within it a resilient piston 35 provided with acentrally located coupling button indicated generically as 36.

When the plunger is withdrawn through the hub to the right as shown inFIG. 1, and the hub is rotated on its pivotal mounting to swing it awayfrom over the open end of the barrel, the cartridge l2 is inserted intothe barrel, needle end first, and the cartridge and barrel aremanipulated to threadedly engage the parts 18 and Ztl. Then the hub isswung back into alignment with the barrel and the plunger 3i) is thrustin to automatically engage the inner end of the plunger with the button.This is possible because of the construction and central position of theplunger and button. The plunger comprises a metal or plastic rod havinga thumb piece 40 at one end and a forked opposite end. While thefurcations may be of any number, for convenience in further descriptionof the invention, the plunger is described as bifurcated. The furcationsextend for a considerable distance from said opposite end to provide, inthe form of invention illustrated, two tines i2 which are normallybiased by inherent resiliency to cause the free ends of the tines tospring apart. FIG. 5 shows the tines in the divergent relationship thatthey assume when the plunger, shown, for example, in FIG. l, is thrustto its furthermost left-hand position in that ligure.

Referring to FIGS. 5 and 6, it will be seen that each of the tines atits end has an arcuate jaw 44, almost semicircular in extent, with aslight gap between the jaws. The jaws have an internal space 46 of adiameter to t snugly about a conical head 49 forming part of the button36 with the inturned ends of the fingers 4% snugly embracing the neckportion 56 of the button. The underside 52 of the head 49 isperpendicular to the longitudinal axis of the button and to the lengthof the piston. The inside faces of the fingers, indicated at 54 in FIG.5 are parallel to the underface of the head 49 of the button when theplunger and button are coupled together. The button itself is of rigidmaterial, as metal, hard rubber or plastic, coupled into the softerresilient material of the piston, with a face of a flange S6 on thebutton extending slightly above the adjacent face of the piston and witha neck 58 and a second head 6@ ernbedded in the resilient material ofthe piston, the head dit having a surface perpendicular to the length ofthe piston, said head, therefore, resisting pulling the button out ofthe piston, the ilange 56 resisting thrust of the button into thepiston.

Reverting to FIGS. 1 and 2, when the cartridge has been positioned inthe barrel and the hub rotated to bring the plunger over the cartridgeand in alignment with the button, the plunger is moved in a distanceuntil the fingers 48 engage the conical head 49 of the button SI5. Atthis time there is a portion of the plunger between the hub and thebutton relatively free of lateral restraint, enabling the tines, onfurther thrust on the plunger, to be sprung apart by the conical head,notwithstanding the holding together of the tines at a position furtherback along the plunger by the bore in the hub, and then snap under thehead into locking engagement with the button. The bore 29, as hasalready been described, snugly slidably accommodates the plunger, andtherefore the tines, when the plunger is retracted or drawn to theright, see FIG. 1, are forced into parallelism thus maintaining thecoupling engagement of the plunger and piston. After initial movement ofthe plunger so as to effect coupling between the plunger and the piston,and after the needle has been inserted into a patient, the piston may bewithdrawn by limited plunger retraction to determine whether the needleis in communication with a vein or an artery. Thus, within a substantialrange of movement of the piston from its initial position at theright-hand end of the barrel, the piston may be reciprocated by theplunger, at will, without decoupling.

The piston may be thrust, by plunger action, toward the needle, thefinger end of the plunger thrusting against the ilange 56 of the button.As the plunger is thrust forward, and when the piston is at or near theneedle end of the cartridge, the bifurcated portion of the plungerleaves the hub and the tines are free to diverge under their inher-entbias, thus disengaging the fingers from beneath the head of the button.The plunger is therefore now free to be retracted Without withdrawal ofthe piston, to enable easy removal of the evacuated cartridge andplacement within the holder of a filled cartridge.

In a modified form of plunger, a portion of which is shown in section inFlG. 8, the tines, whether there be two or more, need not have a biasimparted thereto to cause divergence of the lingers. Instead, the tines,while resilient, are normally biased to parallel position sand the innerfaces of the fingers have a slight bevel 64 imparted thereto so thatupon retraction of the plunger after the dosage of medication has beendelivered through needle 34, the ngers will be cammed apart to releasethe button, thus effecting uncoupling or disengagement of the plungerand piston. There is suiicient friction between the piston and tube toaccomplish this result when the tines are not confined in the bore ofthe hub and they are free to spread apart.

Still greater ease in coupling of the cartridge with the plunger ofeither type described is effected with the modified form of holderdescribed in connection with FIG. 3. 'Ihe holder of FIG. 3 is of a typedisclosed in Patent No. 2,956,563 to Stanley I. Sarnoff dated October18, 1960, to which reference may be made for ampliiication of thedisclosure herein. The holder, see FIGS. 3 and 4, comprises a barrel 7bhaving an end with a bore 72 therein and furcations, here shown as1bifurcations, to form arms 74 which normally tend to spring apart. Thearms have inturned lips 76 at their ends and cams 7 8 on their outerfaces, and a ring Stb surrounding the arms is adapted to be slid fromover the cams to the right, FIG. 3, to allow the arms to assume theirsprung-apart position. The cartridge 12 may now be inserted into theholder by inserting the piston end iirst through the space between thelips '76. The plunger Si), which may be either type previouslydescribed, may preliminarily be advanced in the bore, which snuglyslidably accommodates the plunger, to a position where it is easy forthe tines 42 to be sprung apart and snap over the head t9 of the button36, if the tines are not normally biased to open position. If the tinesare normally biased to open position, the cartridge will move freelyuntil the ange 56 of the button contacts the lingers 48. Furthermovement of the cartridge to loaded position in the holder will thrustthe plunger back to normal initial operative position. ln such operativeposition the bore 72 will provide a camming action and will hold thefingers on the ends of the tines of the plunger closed on the head `ofthe button so that the piston may be retracted for aspirating purposeswithout piston detachment from the plunger. Upon movement of thecoupling end of the plunger and piston close to the needle end of thecartridge, the coupling may be detached or become detached, aspreviously described.

In the case of the form of invention shown in FIG. 3 the plunger can beeasily with-drawn Iwithout dragging the piston back with it, and thering `Sli may then be moved back, -tlius releasing the cartridge forremoval from the holder. The holder may now be reloaded, as has alreadybeen described.

While particular embodiments of this invention have been illustrated anddescribed, modifications thereof will occur to those skilled in the art.lt is to be understood, therefore, that this invention is not to belimited to the particular arrangements disclosed, and it is intended inthe appended claims to cover all modications within the spirit and scope:of this invention.

Having thus described the invention, what is claimed is:

l. A holder comprising a barrel adapted to receive a cartridge with apiston therein,

d a hub, forming part of the holder, provided with a bore therethrough,a plunger snugly slidably reciprocative in said bore, said plungercomprising furcated portions forming a plunger portion slidable in thebore, said furcated portions comprising tines biased to ydiverge rom oneanother and forced toward one another by movement of the furcatedportion in to the bore, and sai-d fui-cated portion terminating inlingers directed to- -ward each other adapted to engage the piston whenthe fingers are brought close together. 2. A holder comprising a barreladapted to receive a cartridge with a piston therein,

said piston having a coupling button having a head with an underface ofthe head perpendicular to the length of the piston, a hub, forming partof the holder, provided with a bore therethrough, e plunger snuglyslidably reciprocative in said bore, said plunger comprising a [furcatedportion forming a plunger portion slidable in the bore, and saidfurcated portion terminating in ngers -directed toward each otheradapted to engage beneath the head of the button :on the piston, Whenthe fingers are brought together, the face of the fingers adapted todirectly engage the underface of the head being bevelled to permit easydisengagement of the plunger from the piston in a predetermined regionof the plunger with respect to the barrel. 3. A holder comprising abarrel adapted to receive a cartridge with a piston therein,

said piston having a coupling button having a head with an underface ofthe head perpendicular to the length of the piston, a hub, forming partof the holder, provided with a bore therethrough, and a plunger snuglyslidable in said bore, said plunger comprising an end portion adapted tobe engaged by a thumb of an operator, an intermediate solid section, andan end portion, said end portion being furcated lto form tines, saidtines being biased to diverge `from one another and forced toward eachother by movement of the furcated portion into the bore, said tineshaving iinger portions formed. on the ends thereof, said linger portionsbeing directed toward each other and adapted to engage the underface ofthe head of the button yand there being a chamber formed between thelingers to accommodate said head. 4. A holder comprising a barreladapted to` receive a cartridge with `a piston therein,

said piston having a coupling button having a head with an underface onthe head perpendicular to the length of the piston, a huib, forming partof the holder, provided with a bore therethrough, a plunger snuglyslidable in said bore, said plunger comprising an end portion adapted tobe engaged by .a thumb of an operator, an intermediate solid section,and an end portion, said end portion being furcated to form tines. saidtines being biased to diverge from one another and forced toward eachother vby movement of the furcated portion into the bore, said tineshaving finger portions Vformed on the ends thereof, said finger portions-being directed toward each other and adapted to engage the underface ofthe head of the button and there being a chamber formed between thefingers to accommodate said head, the face of each finger, which iswithin the chamber,

being bevelled.

5. A holder comprising a barrel adapted to accommodate a cartridgehaving a piston therein,

said barrel having a hub at one end thereof and having -furcatedportions at the other end,

said furcated portions forming arms integral with the hub,

lips at the `free ends of the arms which lips are directed toward eachother,

means for drawing the free ends of the arms toward each o er to retain acartridge within the barrel,

said hub having a lbore therethrough,

a plunger snugly slidably movable in said bore,

said plunger including tines normally biased to diverge from each otherand movable through said bore and inturned lingers on the free ends ofthe tines adapted to `be engaged with the piston when the tines arewithin the bore.

6. The combination with a barrel having a space receiving a cartridgetherein,

said barrel at one end thereof having la hub with a bore therethrough,

a plunger having resilient tines biased to ldiverge away from each otherand slidable snugly in said bore whereby the tines when in the bore willlbe urged together and the lbore will resist spreading `action of thetines, the free ends of said tines having fingers directed toward eachother,

said cartridge having a hollow needle at one end and ya piston thereinat the other end,

a coupling button amxed to the piston,

said button having a head with a face opposed to the lingers wherebywhen the lingers are engaged with the said face, and the pist-on is nearthe `hub of the holder, a body fluid may Ibe aspirated into thecartridge via the hollow needle by a retraction of the plunger, pullingthe piston with it.

7. The combination with a-barrel having a space receiving a cartridgetherein, said barrel having at one end thereof a hub with a boretherethrough,

a plunger having resilient tines biased to diverge away from each otherand sl-idable snugly in said bore whereby the tines when in the borewill be urged together Aand the bore will resist spreading action of thetines, the free ends of said tines having fingers directed toward eachother,

said cartridge having a hollow needle at one end and a piston therein atthe other end,

la coupling button affixed to the piston, said lbutton having -a headwith a face thereof perpendicular to the `length of the piston andopposed to the fingers whereby when the fingers :are engaged with theface and the piston is near the hub of the holder, a lbody fluid may beaspirated into the cartridge via the hollow 6 needle by a retraction ofthe piston, pulling the piston with it. 8. The combination with aIbarrel having a space receiving a cartridge therein, said barrel havingat one end thereof a hub with a bore therethrough,

a plunger having resilient tines biased to diverge away from each otherfand slidable snugly in said bore `whereby the tines, ywhen in the bore,will be urged together and the bore will resist spreading action of thetines,

the free ends of said tines having fingers directed toward each other,

lsaid :cartridge having a hollow needle at one end and a piston thereinat the other end,

a coupling button affixed to the piston, said button having a head 'witha face `opposed to the fingers perpendicular to the length of thepiston, and said fingers having bevelled surfaces to engage said face sothat when the piston is near the needle end of the cartridge, theplunger can be cammed away from the head by retraction of the plunger.

9. A holder comprising a barrel 'adapted to accommodate a cartridgehaving a piston therein,

`said piston having la coupling button having a head with anundersurface on the head perpendicular to the length of the piston,

said barrel having a hub at one end thereof and having furcated portionsat the other end,

said furcated portions forming arms integral with the hub,

lips at the tree ends yof the arms which lips are directed toward eachother,

means for `drawing the free ends of the arms toward each other to retaina cartridge Within the bar-rel,

said hub having a bore therethrough,

a plunger having tines which tines are snugly slida'ble in `said bore,

`and said tines having inturned fingers on the yfree ends thereofadapted to engage the underface of the head of the button and therebeing formed a space between the fingers to accommodate the head,

the face yof each finger, which is directed toward the space between thefingers, ybeing bevelled.

References Qited in the file of this patent UNITED STATES PATENTS1,139,368 Pierce May 11, 1915 1,718,599 Smith June 25, 1929 2,895,773MicConnaughey July 2'1, 1959 2,915,064 Everett et al. Dec. 1, 19592,946,331 lungst July 26, 1960 2,956,563 Sarnoff Oct. 1'8, 1960

2. A HOLDER COMPRISING A BARREL ADAPTED TO RECEIVE A CARTRIDGE WITH APISTON THEREIN, SAID PISTON HAVING A COUPLING BUTTON HAVING A HEAD WITHAN UNDERFACE OF THE HEAD PERPENDICULAR TO THE LENGTH OF THE PISTON, AHUB, FORMING PART OF THE HOLDER, PROVIDED WITH A BORE THERETHROUGH, APLUNGER SNUGLY SLIDABLY RECIPROCATIVE IN SAID BORE, SAID PLUNGERCOMPRISING A FURCATED PORTION FORMING A PLUNGER PORTION SLIDABLE IN THEBORE, AND SAID FURCATED PORTION TERMINATING IN FINGERS DIRECTED TOWARDEACH OTHER ADAPTED TO ENGAGE BENEATH THE HEAD OF THE BUTTON ON THEPISTON, WHEN THE FINGERS ARE BROUGHT TOGETHER, THE FACE OF THE FINGERSADAPTED TO DIRECTLY ENGAGE THE UNDERFACE OF THE HEAD BEING BEVELLED TOPERMIT EASY DISENGAGEMENT OF THE PLUNGER FROM THE PISTON IN APREDETERMINED REGION OF THE PLUNGER WITH RESPECT TO THE BARREL.